Intermittent driving mechanism for timepiece

ABSTRACT

An intermittent driving mechanism for timepieces, comprising a balance, a driving wheel having an odd number of teeth, and two impulse plates provided on the balance and disposed in an axially spaced relation on diametrally opposite sides of the driving wheel for causing intermittent rotation of said driving wheel by alternately striking teeth on the driving wheel, whereby each intermittent rotative motion of the driving wheel brings two adjacent teeth of the driving wheel into contact with the last striking plate, thereby obstructing the free rotation of said driving wheel, and stopping the driving wheel until a tooth is struck by the other plate.

United States Patent Yamada [54] INTERMITTENT DRIVING MECHANISM FOR TIMEPIECE [72] lnventor: Asahiro Yamada, 2-3-2, Kakinokisaka, Meguro-ku, Japan 22 Filed: May 28,1970

{21] Appl. No.: 41,256

[30] Foreign Application Priority Data 1 Feb. 29, 1972 3,444,747 5/ 1969 Von Zeppelin et al. .58]! 16 X Primary ExaminerRichard B. Wilkinson Assistant Examiner-Edith C. Simmons Attorney-Robert E. Burns and Emmanuel J. Lobato [57] ABSTRACT An intermittent driving mechanism for timepieces, comprising a balance, a driving wheel having an odd number of teeth, and

two impulse plates provided on the balance and disposed in an axially spaced relation on diametrally opposite sides of the May 28, 1969 Japan ..44/48672 driving wheel f causing intermittent rotation f said driving wheel by alternately striking teeth on the driving wheel. [52] US. Cl. ..58/28 I), 58/855 h r by gach int rmittent rotative motion of the driving [51] Int. Cl. ..G04c 3/04, G04b 27/00 wheel brings two adjacent teeth of the driving wheel into conl l Fleld Search 23 tact with the last striking plate, thereby obstructing the free 58/855 rotation of said driving wheel, and stopping the driving wheel until a tooth is struck by the other plate. [56] References Cited 5 Claims, 8 Drawing Figures UNITED STATES PATENTS 3,296,790 l/l967 Schwaar s/s5.s

nTITr Patented Feb. 29, 1972 3,645,089

2 Sheets-Sheet 1 FIG. I m 2 v5 mm x mm? '34 7% g m 1L 9 Ff 6"' 111 I9 |Q Ill ip" I l3 U Patented Feb. 29, 1972 I 3,645,089

2 Sheets-Sheet 2 INTERMITTENT DRIVING MECHANISM FOR TIMEPIECE The invention relates to an intermittent driving mechanism for converting a reciprocating rotation of a balance in a time measuring mechanism into an intermittent rotation to be given to. the hands.

In atimepiece having a second hand, an intermittent rotation is transmitted from the driving wheel of the intermittent driving mechanism to the second hand arbor through a gear train, and thence it is transmitted via a gear train to the minute hand arbor and the hour hand arbor. In the field of intermittent driving. mechanisms, there is known in the art a mechanism comprising a balance for reciprocating rotation, a driving wheel, and two elongated pins mounted to protrude from the balance staff for driving the driving wheel in such a, manner that, during the forward travel of said balance in the reciprocating rotation, either pin causes the rotation of the driving wheel by a certain angle, and then, during the return travel,-the other pin causes the rotation of the driving wheel by a certain angle in the same direction. This conventional mechanism is equipped with a ratchet secured fixedly to the driving wheel, and a click spring in engagement with the ratchet for maintaining the intermittent rotation of the driving wheel at a constant angle either way, for keeping the driving wheel motionless and inoperative after each rotation. However, this type of mechanism has a disadvantage in that the second hand is moved together with the minute and hour hands when either of the latter hands is adjusted while the click spring is incompletely engaged with the ratchet, in the course of shifting from the engagement with the bottom of one tooth to another, upon striking or beating of one driving wheel tooth by one of the elongated pins.

The present invention eliminates the foregoing disadvantage of the conventional intermittent driving mechanism and provides a new, improved intermittent driving mechanism for timepieces.

In one aspect of the invention, an intermittent driving mechanism for timepieces is provided which comprises a balance for reciprocating rotation; a driving wheel having a plurality of equally spaced teeth, said plurality comprising an odd number; two impulse plates provided on the balance for alternately beating the teeth of the drivingwheel for intermittent rotation thereof; and detent means for keeping the driving wheel in a still and resting position after each intennittent rotation. The two impulse plates have a width greater than the distance between two adjacent teeth of the driving wheel, and are disposed spaced from each other in the axial direction of the balance and also at a certain phase angle with respect of each other in the rotating direction of said balance, the center of rotation of said driving wheel being located in the center of the. axial distance between the impulse plates, thereby enabling the impulse plates to come into contact with two adjacent teeth of the driving wheel in alternate beating of the driving wheel by said impulse plates. Thus, when either impulse plate beats a tooth of the driving wheel, the plate contacts two teeth, i.e., the tooth just beaten and a neighboring tooth, so as to keep the driving wheel from rotating without load. Next, the moment the above impulse plate has moved away from thetwo teeth, the detent means keeps the driving wheel in a still and resting position. This arrangement precludes rotationof the second hand in company with the minute hand and hour hand of the timepiece while the latter hands are being adjusted.

Thus, it is an object of the present invention to provide an intermittent driving mechanism for timepieces which can continue accurate intermittent rotation without being affected by adjustment of the hands.

Other features, advantages and objects of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front elevational view of a partial watch movement embodying the invention;

FIG. 2 is a side elevational view of the device shown in FIG. I, with the balance removed;

FIG. 3 is a sectional view taken along the line III-III of FIG.

FIGS. 44 to 40 are sequential diagrammatic views showing how the impulse plates beat the driving wheel;

FIG. 5 is a front elevational view of a more complete watch movement embodying the invention; and,

FIG. 6 is a front elevational view of another form of driving wheel according to the invention.

Referring to FIGS. 1 to 3, a balance generally indicated at I consists of two balance wheels 3 and 4 fixed to a balance staff 2, which in turn is rotatably supported at the upper and lower ends. To cause reciprocating rotation of this balance, an electromagnetic driving device of an ordinary design is used. Magnets 5 and 6, constituting parts of the device, are fixedly secured to the opposing faces of the balance wheels 3 and 4. Also, between the magnets 5 and 6 there is disposed a coil 7 for both pickup and driving purposes which electromagnetically acts on the magnets. The showing of electric circuits has been omitted for simplicity. Masses 8 and 9 are secured to the balancewheels 3 and 4 on the sides opposite to the magnets 5 and 6 for counterbalancing the magnets.

A driving wheel 10 formed with five teeth 11 is securely mounted on a spindle 12, which is supported rotatably in the direction normal to the balance staff 2. Also securely mounted on the spindle l2, behind the driving wheel 10, is a ratchet 13 which is formed with 10 teeth, or twice as many as the teeth of the driving wheel, and a driving pinion 14. A click spring 15, fixed at the base end to a stud 16, has an angularly bent tip 17 for resiliently engaging the teeth of the ratchet l3.

Underneath the balance, a sleeve 18 is fixedly attached to the balance staff 2, and segmental impulse plates 19 and 20 are secured, respectively, to the upper and lower ends of the sleeve. Each impulse plate has a width greater than the distance between two adjacent teeth of the driving wheel. The plane of rotation of one impulse plate 19 passes substantially tangentially of the pitch circle at the upper part of the driving wheel 10, while that of the other impulse plate 20 passes substantially tangentially of the pitch circle at the lower part of the driving wheel. The impulse plates 19 and 20 are staggered at a suitable'phase angle in their directions of rotation, and the width and phase angle of the impulse plates are so determined that each plate in its forward travel within a predetermined range of angle of reciprocating rotation can come into contact with two adjacent teeth of the driving wheel and, in the return travel, it can move completely away from the circle of the driving wheel.

In the operation of the intermittent driving mechanism the electromagnetic driving device causes reciprocating rotation of the balance 1 within a certain angular range. In the clockwise turning of the balance 1 in the course of the reciprocating rotation, the impulse plates 19 and 20 begin to move in the directions indicated by arrows in FIG. 40. Next, one impulse plate 19 beats one tooth ll of the driving'wheel I0 as shown in FIG. 4b and forces the driving wheel and ratchet to turn in the arrow-marked directions, thereby urging the tip of click 17 of the click spring 15 away from the bottom of one tooth of the ratchet 13 to an incompletely engaged state'as shown in FIG. 4b. In prior art devices, if the spindle 12 which carries the driving wheel is quickly turned while this state of incomplete engagement is maintained, the ratchet 13 and the driving wheel 10 tend to rotate freely without any restricting action of the click spring 15. However, in the device disclosed herein, both are kept from rotating freely, because the impulse plate 19 is allowed to come into engagement with the tooth just beaten and the adjacent tooth at the right of the driving wheel, thereby preventing such free rotation. That is, as the impulse plate 19 moves further, to the position as in FIG. 4c, it comes into contact with the two adjacent teeth of the driving wheel 10 to stop the wheel completely in the position where the latter'has turned by the given angle. In this state the tip 17 of the click spring 15 fully engages the bottom of the following tooth of the ratchet 13, and holds the ratchet and wheel stationary. 1n the movement of the impulse plates 19 and 20, in the direction opposite to those described above, the other impulse plate 20 performs the beating of the driving wheel and restriction of the wheel against rotation just in the same manner as explained in connection with the impulse plate 19, so that the driving wheel is likewise caused to rotate by a certain angle in the direction indicated by an arrow. Each beat by either of the impulse plates- 19 and 20 causes turning of the driving wheel 10 by an angle equivalent to one-half of a tooth (i.e., 36), which is accompanied by the turning of the ratchet 13 by one tooth.

As shown in FIG. 5, the intermittent rotation of the driving pinion 14 is transmitted to a second-hand arbor 23 through a lO-second wheel 21 in mesh with the pinion 14, a 10-second pinion 22 which is secured to the arbor of the IO-second wheel, and a second hand wheel 24 secured to the second hand arbor, which arbor carries a second hand 25 at its tip. A second hand pinion 26 is fixed to the second hand arbor 23, and the rotation of the second hand pinion is transmitted by a counter wheel 28 in mesh therewith and a counter pinion 29, both fixedly secured to an arbor 27, to a minute hand wheel which is in mesh with the counter pinion 29 and is mounted for free rotation about the second hand arbor 23. A minute hand pinion 32 is secured to a minute hand arbor 31, also mounted for free rotation about the second hand arbor 23, and the minute hand wheel 30 is resiliently pressed against the minute hand pinion 32 by a friction spring washer 33 which is fitted to the second hand arbor 23. The minute hand arbor 31 carriesa minute hand 34 at its tip. Rotation of the minute hand pinion 32 is transmitted to an hour hand arbor 38 by a minute wheel 36 and a minute pinion 37, both secured to an arbor which in turn is mounted for free rotation about the arbor 27, and also an hour hand wheel 39 secured to the hour hand arbor 38 which is mounted for free rotation about the minute hand arbor 31. Similarly, an hour hand 40 is attached to thetip of the hour hand arbor 38. An arbor 42 for an adjusting button 41 is slidably supported in the wall of the timepiece, and a third adjusting wheel 43, secured to the tip of the arbor 42, is brought into or out of engagement with a second adjusting wheel 44 by pushing or pulling the button 41. The rotation of the second adjusting wheel 44 is transmitted to the minute wheel 36 through a first adjusting wheel 45. The click spring 15 which engages the ratchet 13 is capable of exerting sufficient pressure to resist the slipping torque which is transmitted from the minute hand wheel 30 to the driving pinion 14 via the second hand wheel 24, lO-second pinion 22, and then second wheel 21, by virtue of the spring washer 33.

Adjustment of the minute hand 34 and the hour hand 40 is accomplished by turning the button 41, while the third adjusting wheel 43 and the second adjusting wheel 44 are engaged with each other, thereby causing the minute hand arbor 31 and the hour hand arbor 38 to rotate. During the rotation of the minute hand arbor 31 for hand adjustment, the driving wheel 10 is kept from free rotation by the two impulse plates 19 and 20 and the click spring 15. Therefore, the minute hand wheel 30 slips between the driving wheel and the minute hand arbor 31, thus preventing the transmission of the rotation of the minute hand arbor 31 for the hand adjustment to the driving wheel 10.

The driving wheel 10 for the embodiment of the invention so far described may be replaced by one having three, seven or some other odd number of teeth, provided the ratchet has' twice as many teeth as the driving wheel.

FIG. 6 shows a generally pentagonal driving wheel 110, having teeth 111, and being mounted on an arbor 112, in a similar manner as compared to the counterparts shown in FIGS. 1 to 3.

I claim:

1. In an intermittent driving mechanism for timepieces, including balance means mounted within a timepiece for reciprocating rotation; a driving wheel having an odd number of equally spaced teeth projecting radially therefrom; im ulse means connected to said balance means for alternately eating the teeth of said driving wheel for intermittently rotating said driving wheel; and means for keeping the driving wheel motionless after such intermittent rotation: the improvement wherein said impulse means comprises two impulse plates axially spaced on said balance means for rotation through respective planes which pass tangentially and diametrally at opposite sides of said driving wheel, said impulse plates each having a width greater than the distance between two adjacent teeth of the driving wheel, and being angularly displaced with respect to each other in the rotating direction of said balance means, wherein the impulse plates come into contact with two adjacent teeth of the'driving wheel in alternate beating of the driving wheel by said impulse plates.

2. The invention as set forth in claim 1, in which said means for keeping the driving wheel motionless comprises a ratchet concentrically attached to the driving wheel, and click spring means resiliently and removably engaged with the teeth of said ratchet.

3. The invention as set forth in claim 2, in which said ratchet has twice as many teeth as said driving wheel.

4. The invention as set forth in claim 1, in which the timepiece has movable time-indicating means for being driven in response to movement of said driving wheel, and further comprising means for adjusting said time-indicating means, gear means interconnecting said driving wheel with said timeindicating means, and means for releasing the gear means interconnection of said driving wheel and time-indicating means when said means for adjusting said time-indicating means is being operated.

5. The invention as set forth in claim 4, in which said means for keeping the driving wheel motionless comprises a ratchet concentrically attached to the driving wheel, and click spring means resiliently and removably engaged with the teeth of said ratchet. 

1. In an intermittent driving mechanism for timepieces, including balance means mounted within a timepiece for reciprocating rotation; a driving wheel having an odd number of equally spaced teeth projecting radially therefrom; impulse means connected to said balance means for alternately beating the teeth of said driving wheel for intermittently rotating said driving wheel; and means for keeping the driving wheel motionless after such intermittent rotation: the improvement wherein said impulse means comprises two impulse plates axially spaced on said balance means for rotation through respective planes which pass tangentially and diametrally at opposite sides of said driving wheel, said impulse plates each having a width greater than the distance between two adjacent teeth of the driving wheel, and being angularly displaced with respect to each other in the rotating direction of said balance means, wherein the impulse plates come into contact with two adjacent teeth of the driving wheel in alternate beating of the driving wheel by said impulse plates.
 2. The invention as set forth in claim 1, in which said means for keeping the driving wheel motionless comprises a ratchet concentrically attached to the driving wheel, and click spring means resiliently and removably engaged with the teeth of said ratchet.
 3. The invention as set forth in claim 2, in which said ratchet has twice as many teeth as said driving wheel.
 4. The invention as set forth in claim 1, in which the timepiece has movable time-indicating means for being driven in response to movement of said driving wheel, and further comprising means for adjusting said time-indicating means, gear means interconnecting said driving wheel with said time-indicating means, and means for releasing the gear means interconnection of said driving wheel and time-indicating means when said means for adjusting said time-indicating means is being operated.
 5. The invention as set forth in claim 4, in which said means for keeping the driving wheel motionless comprises a ratchet concentrically attached to the driving wheel, and click spring means resiliently and removably engaged with the teeth of said ratchet. 